Much as a river current carries a pebble, fluid flows can carry particulates such as nanoparticles and microcapsules. While mechanical pumps are conventionally used to drive fluid flow, chemical "pumps" can also propel fluid by using chemical reaction networks to create gradients in chemical concentrations and fluid densities. Researchers in the NSF Center for Chemo-Mechanical Assembly (CCMA) are creating new transformative tools to enable unprecedented control over fluid flow and particle organization in confined environments. These precisely controlled fluid flows enable the design of self-powered, self-sustaining systems that organize particles and are capable of performing complex functions such as an autonomous nanoparticle system that detects a chemical source and collectively delivers a response chemical to it resulting in a vital analysis or creation of a novel structure. The CCMA team includes expertise in catalysis, synthetic chemistry, physical chemistry, fluid flow, and modeling. In addition to providing the chemistry community with new chemical reaction network tools, CCMA is also contributing to science and technology workforce development by training students in multidisciplinary experimental and modeling techniques. Through its industry affiliates program, CCMA is engaging industry in student training and technology transfer. Concurrent with the research, the team is launching a vigorous program of education and outreach to the public. This includes expanding undergraduate and graduate research opportunities for underrepresented groups in research-based careers. The team is also participating in several large-scale public outreach programs including public lectures, designing hands-on traveling exhibits, and teaming with museums and science centers.
Through collaborative research that combines innovative modeling and experimental studies, the NSF CCI Phase I: Center for Chemo-Mechanical Assembly (CCMA) is harnessing catalytic chemical reactions to introduce spatiotemporal chemical gradients that drive the flow of a surrounding fluid. This flow, in turn, enables the manipulation of the collective behavior of suspended particles to drive new modes of dynamic self-organization. The Center is developing novel approaches to cause directed transport of nano- and micron-scale materials, control particle organization in confined chambers, and establish new chemical routes for regulating non-equilibrium structure formation from particles in solution. These studies are providing the chemistry community with fundamentally new tools and knowledge, including new chemistries for the creation of catalytic cascades; determination of design rules for chemical feedback loops; demonstration of new modes of out-of-equilibrium assembly; and progress toward new understanding of the nonlinear behavior and auto-amplification emerging from these systems. Potential applications include the creation of standalone microfluidic devices that autonomously perform multi-stage chemical reactions and assays for portable biomedical applications; automated materials assembly in harsh environments; and small-scale factories that can operate autonomously to build microscale components for use in fine instrumentation and robotic systems, and, in parallel, to screen for optimal reaction parameters yielding micro-machines with specified properties. To generate excitement and public appreciation about this emerging area of chemistry, the CCMA team is participating in several large-scale public outreach programs at the participating institutions, including public lectures, hands-on traveling exhibits, and museum and science center projects.
